Indolizine derivatives, compositions comprising at least one coupler chosen from indolizine derivatives and at least one oxidation base, and methods for using same

ABSTRACT

Compositions for oxidation dyeing of keratin fibers comprising at least one oxidation base and at least one coupler chosen from indolizine derivatives, methods for using the same for oxidation dyeing of keratin fibers, and compounds chosen from indolizine derivatives.

[0001] The present invention relates to compositions for oxidationdyeing of keratin fibers comprising at least one oxidation base and atleast one coupler chosen from specific indolizine derivatives.

[0002] Dye compositions comprising oxidation dye precursors are known inthe art for dyeing keratinous fibers, such as human hair. The oxidationdye precursors include ortho-phenylenediamines, para-phenylenediamines,ortho-aminophenols, para-aminophenols, and heterocyclic compounds. Theseare generally known as oxidation bases. The oxidation dye precursors, oroxidation bases, are generally colorless or weakly colored compoundswhich may give rise to colored compounds and dyes when combined withoxidizing products via oxidative coupling.

[0003] The shades obtained with these oxidation bases may be varied bycombining them with couplers or coloration modifiers. Such colorationmodifiers may, for example, be chosen from aromatic meta-diamines,meta-aminophenols, meta-diphenols, and certain heterocyclic compounds,such as indole compounds. The variety of oxidation bases and couplersmay allow a rich palette of colors to be obtained.

[0004] The so-called “permanent” coloration obtained from using theseoxidation dyes should have at least one of the following desirablecharacteristics. The coloration should have no toxicological drawbacks,the shades obtained should have the desired intensity, and thecoloration should have good resistance to external agents to which thefibers may be subjected, such as light, bad weather, washing,permanent-waving, perspiration, and rubbing. The dyes should allowcoverage of white hairs, and should be as unselective as possible, thatis, they should allow only the smallest possible differences incoloration along the same keratin fiber, which may be differentlysensitized (i.e. damaged) between its end tip and its root.

[0005] Indazole-type compounds have been used in the field of hairdyeing. For example, in DE-A-1 492 166, the disclosure of which isincorporated herein by reference, the polycondensation of such compoundsvia oxidation has been proposed, in DE-A-2 623 564, the disclosure ofwhich is incorporated herein by reference, it has been proposed tocombine hydroxy-indazoles with tetraaminopyrimidines, and in U.S. Pat.No. 4,013,404, the disclosure of which is incorporated herein byreference, certain aminoindazoles and their use as oxidation dyeprecursors have been proposed.

[0006] The inventors have discovered that it may be possible, by usingspecific indolizine derivatives, to obtain novel dyes which are at leastone of the following: powerful, unselective, resistant, and capable ofgenerating intense colorations in varied shades.

[0007] Specifically, one subject of the present invention is acomposition for oxidation dyeing of keratin fibers comprising, in amedium suitable for oxidation dyeing:

[0008] (i) at least one oxidation base; and

[0009] (ii) at least one coupler chosen from indolizine derivatives offormula (I) and the acid addition salts thereof:

[0010] wherein:

[0011] n is an integer ranging from 0 to 4;

[0012] R₁ and R₃, which may be identical or different, are each chosenfrom a hydrogen atom; halogen atoms; C₁-C₄ alkyl radicals; C₁-C₄ alkoxyradicals; C₁-C₄ monohydroxyalkyl radicals; C₂-C₄ polyhydroxyalkylradicals; C₁-C₄ aminoalkyl radicals; acetylamino radicals;acetylamino(C₁-C₄)alkyl radicals; (C₁-C₄)alkoxy(C₁-C₄)alkyl radicals;mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals;di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; aminocarboxy(C₁-C₄)alkylradicals; acetyl(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; and aromaticrings, optionally substituted with at least one radical chosen fromhalogen atoms, C₁-C₄ alkyl radicals, trifluoromethyl radicals, C₁-C₄alkoxy radicals, amino radicals and mono- and disubstituted aminoradicals wherein the substituent is chosen from C₁-C₄ alkyl radicals,(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, di(C₁-C₄)alkylamino(C₁-C₄)alkylradicals, carboxyl radicals and sulphoxy radicals;

[0013] wherein R₃ may optionally further be chosen from 5- and6-membered unsaturated heterocycles; and

[0014] with the proviso that at least one of R₁ and R₃ is a hydrogenatom;

[0015] R₂ and R₄, which may be identical or different, are each chosenfrom a hydrogen atom, halogen atoms, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals, C₁-C₄aminoalkyl radicals, mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals, cyanoradicals, carboxy(C₁-C₄)alkyl radicals, nitro radicals, and 5- and6-membered aromatic rings, optionally substituted with at least oneradical chosen from halogen atoms, C₁-C₄ alkyl radicals, trifluoromethylradicals, C₁-C₄ alkoxy radicals, amino radicals and mono- anddisubstituted amino radicals wherein the substituent is chosen fromC₁-C₄ alkyl radicals, (C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals and sulphoxyradicals.;

[0016] As used herein, “at least one” means one or more and thusincludes individual components as well as mixtures/combinations.Further, as used herein, unless otherwise noted, alkyl radicals may bechosen from substituted, unsubstituted, linear, branched, and cyclicalkyl radicals. Similarly, as used herein and unless otherwise noted,the alkyl radicals of alkoxy radicals may be chosen from substituted,unsubstituted, linear, branched, and cyclic alkyl radicals.

[0017] Non-limiting examples of 6-membered aromatic rings of formula (I)include phenyl rings, nitrophenyl rings, alkylphenyl rings, alkoxyphenylrings, polyalkyl-phenyl rings and polyalkoxyphenyl rings.

[0018] Non-limiting examples of unsaturated 5- and 6-memberedheterocycles include pyrrole rings, pyridine rings, pyrimidine rings,imidazole rings, pyrazole rings, oxazole rings, thiazole rings, triazolerings, pyrazolotriazole rings, pyrazoloimidazole rings, pyrrolotriazolerings, pyrazolopyrimidine rings, pyrazolopyridine rings, benzimidazolerings, benzoxazole rings, benzothiazole rings, indole rings, indolinerings, indolidine rings, isoindolidine rings, benzotriazoline rings,pyrazine rings, oxazine rings, triazine rings, quinoline rings,tetrahydro-quinoline rings, benzimidazolidine rings and benzopyrimidinerings.

[0019] Compounds comprised within those of formula (I) may be known, forexample, in the field of photography, and methods of preparing this typeof compound may be disclosed in Chichibabin, Ber. 1927, 60, 1607;Borrows et al., J. Chem. Soc., 1946, 1069; and/or T. Uchida et al.,Synthesis, 1976, 209-236.

[0020] Colorations obtained using the inventive dye compositions maypossess at least one of the following desirable characteristics:unselectivity, power, ability to enable a variety of shades, andexcellent properties of resistance to at least one of atmospheric agentschosen from light and bad weather, perspiration and treatments to whichthe hair may be subjected (such as shampooing, permanent-waving, etc.).

[0021] In one embodiment, indolizine derivatives of formula (I) arechosen from:

[0022] indolizine;

[0023] 2-methyl-1-phenylindolizine;

[0024] 2,8-dimethylindolizine;

[0025] methyl 2-methylindolizine-6-carboxylate;

[0026] 2,7-dimethylindolizine;

[0027] 2-methyl-1-(4-nitrophenyl)indolizine;

[0028] 8-methyl-2-phenylindolizine;

[0029] 2-methylindolizine;

[0030] 7-methyl-2-phenylindolizine;

[0031] 2-phenylindolizine;

[0032] 7-methyl-2-(3-nitrophenyl)indolizine;

[0033] 7-methyl-2-(2,5-dimethoxyphenyl)indolizine;

[0034] 2-(2-pyridyl)indolizine;

[0035] 2-(4-N,N-dimethylaminophenyl)indolizine;

[0036] 2-phenyl-3-[2-(4-pyridyl)ethyl]indolizine;

[0037] 2-phenyl-3-[2-(2-pyridyl)ethyl]indolizine;

[0038] 2-ethyl-7-methoxyindolizine;

[0039] 2-ethyl-8-methoxyindolizine;

[0040] ethyl 2-butyl-7-indolizinecarboxylate;

[0041] 1-ethylindolizine;

[0042] 6,8-dimethylindolizine;

[0043] 5-ethyl-7-methylindolizine;

[0044] N,N-diethyl-2-methyl-1-indolizinethanamine;

[0045] N,N-dimethyl-2-methyl-1-indolizinethanamine;

[0046] N-ethyl-2-methyl-1-indolizinethanamine;

[0047] N-methyl-2-methyl-1-indolizinethanamine;

[0048] 2-methyl-1-indolizinethanamine;

[0049] 5,7-dimethylindolizine;

[0050] 8-cyano-2-methylindolizine;

[0051] 1-ethyl-2-methylindolizine;

[0052] 5-indolizineacetic acid;

[0053] dihydroindolizine;

[0054] 1-indolizinealanine;

[0055] 6-ethyl-1,2-dimethylindolizine;

[0056] 3-ethylindolizine;

[0057] 2-ethyl-1-methylindolizine;

[0058] N,N-diethyl-2-methyl-3-indolizinethanamine;

[0059] N-ethyl-2-methyl-3-indolizinethanamine;

[0060] N-ethyl-N-[2-(2-methyl-3-indolizinyl)ethyl]acetamide;

[0061] N-[2-(2-methyl-3-indolizinyl)ethyl]acetamide;

[0062] N,N,2-trimethyl-3-indolizinethanamine;

[0063] N,2-dimethyl-3-indolizinethanamine;

[0064] 2-methyl-3-indolizinethanamine;

[0065] ethyl 7-indolizinecarboxylate;

[0066] ethyl 6-indolizinecarboxylate;

[0067] N,N-diethyl-2-methyl-3-indolizinepropanamine;

[0068] N-ethyl-N-[3-(2-methyl-3-indolizinyl)propyl]acetamide;

[0069] N-ethyl-2-methyl-3-indolizinepropanamine;

[0070] N-[3-(2-methyl-3-indolizinyl)propyl]acetamide;

[0071] N,N,2-trimethyl-3-indolizinepropanamine;

[0072] N,2-dimethyl-3-indolizinepropanamine;

[0073] 2-methyl-3-indolizinepropanamine;

[0074] 2-methyl-8-nitroindolizine;

[0075] 2-methyl-6-nitroindolizine;

[0076] N,N′-dimethyl-1,2-indolizinethanamine;

[0077] methyl 2-methyl-7-indolizinecarboxylate;

[0078] ethyl 2-methyl-7-indolizinecarboxylate;

[0079] 2-methyl-7-indolizinecarboxamide;

[0080] N-ethyl-2-indolizinethanamine;

[0081] N-methyl-2-indolizinethanamine;

[0082] ethyl 2-methyl-8-indolizinecarboxylate;

[0083] 2-methyl-8-indolizinecarboxylic acid;

[0084] 2-methyl-6-methoxyindolizine;

[0085] 2,8-dimethylindolizine;

[0086] 8-methylindolizine;

[0087] N-[(2-methyl-7-indolizinyl)methyl]acetamide;

[0088] 7-(aminomethyl)-2-methylindolizine;

[0089] 2-methyl-7-indolizinecarboxamide;

[0090] 1-β-hydroxyethyl-2-methylindolizine;

[0091] 6-hydroxymethyl-2-methylindolizine;

[0092] ethyl 6-carboxy-2-methylindolizine;

[0093] 1-hydroxymethylindolizine;

[0094] 2-aminomethylindolizine;

[0095] 2-hydroxymethylindolizine;

[0096] 2,3,7-trimethylindolizine;

[0097] 2,3,6-trimethylindolizine;

[0098] 5-methylindolizine;

[0099] 3,5-dimethylindolizine;

[0100] 1-methylindolizine;

[0101] 2-methylindolizine;

[0102] 7-methylindolizine;

[0103] 6-methylindolizine;

[0104] 3-methylindolizine;

[0105] 6-ethyl-2,3-dimethylindolizine;

[0106] 6-ethyl-2-methylindolizine;

[0107] 1,2-dimethylindolizine;

[0108] 2,7-dimethylindolizine;

[0109] 2,6-dimethylindolizine;

[0110] 2,5-dimethylindolizine;

[0111] 2,3-dimethylindolizine;

[0112] 2-(3-furanyl)indolizine;

[0113] 2-(2-thiazolyl)indolizine;

[0114] 2-(3-thienyl)indolizine;

[0115] 2-(2-thienyl)indolizine;

[0116] 5,7-dimethyl-2-phenylindolizine;

[0117] 2-(3,4-dimethoxyphenyl)indolizine;

[0118] 5-carboxy-2-phenylindolizine;

[0119] 4-(7-indolizinyl)benzenesulphonic acid;

[0120] 4-(2-indolizinyl)benzenesulphonic acid;

[0121] 3,8-dimethyl-2-phenylindolizine;

[0122] 3,7-dimethyl-2-phenylindolizine;

[0123] 3,6-dimethyl-2-phenylindolizine;

[0124] 3,5-dimethyl-2-phenylindolizine;

[0125] 7-methyl-8-nitro-2-phenylindolizine;

[0126] 7-methyl-6-nitro-2-phenylindolizine;

[0127] 1-β-aminoethyl-2-phenylindolizine;

[0128] 8-methyl-2-phenylindolizine;

[0129] 2-(3-methoxyphenyl)indolizine;

[0130] 6-ethyl-2-phenylindolizine;

[0131] 2-(2,5-dimethoxyphenyl)-5-methylindolizine;

[0132] 2-(2,5-dimethoxyphenyl)indolizine;

[0133] 6-methyl-2-phenylindolizine;

[0134] 8-carboxy-2-phenylindolizine;

[0135] 2-(4-γ-hydroxypropylphenyl)indolizine;

[0136] 2-(4-β-hydroxyethylphenyl)indolizine;

[0137] 8-nitro-2-phenylindolizine;

[0138] 6-nitro-2-phenylindolizine;

[0139] 6-carboxy-2-phenylindolizine;

[0140] 6-carboxy-2-phenylindolizine;

[0141] 5-methyl-2-phenylindolizine;

[0142] 7-methoxy-2-phenylindolizine;

[0143] 1-[2-(dimethylamino)ethyl]-2-phenylindolizine;

[0144] 1-[3-(dimethylamino)propyl]-2-phenylindolizine;

[0145] 1-[(dimethylamino)methyl]-2-phenylindolizine;

[0146] 2-(4-methoxyphenyl)indolizine; and the acid addition salts of anyof the foregoing.

[0147] According to the present invention, the at least one coupler maybe present in the composition in an amount generally ranging from0.0005% to 12% by weight relative to the total weight of the dyecomposition, such as from 0.005% to 6% by.

[0148] The nature of the at least one oxidation base used in the presentinvention may not be critical. In one embodiment, the at least oneoxidation base is chosen from para-phenylenediamines, double bases,para-aminophenols, ortho-aminophenols, heterocyclic oxidation bases, andthe acid addition salts of any of the foregoing. As used herein, “doublebases” means compounds comprising at least two aromatic entitiessubstituted with at least one radical chosen from amino radicals andhydroxyl radicals.

[0149] Non-limiting examples of para-phenylenediamines which can be usedas the at least one oxidation base include compounds of formula (II) andthe acid addition salts thereof:

[0150] wherein:

[0151] R₅ is chosen from a hydrogen atom, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals,(C₁-C₄)alkoxy(C₁-C₄)alkyl radicals, C₁-C₄ alkyl radicals substitutedwith at least one radical chosen from nitrogen-containing radicals,phenyl radicals and 4′-aminophenyl radicals;

[0152] R₆ is chosen from a hydrogen atom, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals,(C₁-C₄)alkoxy(C₁-C₄)alkyl radicals and C₁-C₄ alkyl radicals substitutedwith at least one nitrogen-containing radical;

[0153] R₇ is chosen from a hydrogen atom, halogen atoms such as achlorine atom, a bromine atom, an iodine atom and a fluorine atom, C₁-C₄alkyl radicals, C₁-C₄ monohydroxyalkyl radicals, C₁-C₄ hydroxyalkoxyradicals, acetylamino(C₁-C₄)alkoxy radicals, mesylamino-(C₁-C₄)alkoxyradicals and carbamoylamino(C₁-C₄)alkoxy radicals;

[0154] R₈ is chosen from a hydrogen atom, halogen atoms and C₁-C₄ alkylradicals.

[0155] Non-limiting examples of nitrogen-containing radicals of aboveformula (II) include amino radicals, mono(C₁-C₄)alkylamino radicals,di(C₁-C₄)alkylamino radicals, tri(C₁-C₄)alkylamino radicals,monohydroxy(C₁-C₄)alkylamino radicals, imidazolinium radicals andammonium radicals.

[0156] Non-limiting examples of para-phenylenediamines of formula (II)include para-phenylenediamine, para-tolylenediamine,2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,4-amino-N,N-diethyl-3-methylaniline,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-N,N-bis(β-hydroxyethyl)amino-2-methylaniline,4-N,N-bis(β-hydroxyethyl)amino-2-chloroaniline,2-β-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine,2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,2-hydroxymethyl-para-phenylenediamine,N,N-dimethyl-3-methyl-para-phenylenediamine,N-ethyl-N-(β-hydroxyethyl)-para-phenylenediamine,N-(β,γ-dihydroxy-propyl)-para-phenylenediamine,N-(4′-aminophenyl)-para-phenylenediamine,N-phenyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2-β-acetylamino-ethyloxy-para-phenylenediamine,N-(β-methoxyethyl)-para-phenylenediamine, and the acid addition salts ofany of the foregoing.

[0157] In one embodiment, para-phenylenediamines of formula (II) arechosen from am para-phenylenediamine, para-tolylenediamine,2-isopropyl-para-phenylenediamine,2-β-hydroxyethyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,3-dimethyl-para-phenylenediamine,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,2-chloro-para-phenylenediamine,2-β-acetylaminoethyloxy-para-phenylenediamine, and the acid additionsalts of any of the foregoing.

[0158] Non-limiting examples of double bases which may be used as the atleast one oxidation base according to the present invention includecompounds of formula (III) and the acid addition salts thereof:

[0159] wherein:

[0160] Z₁ and Z₂, which may be identical or different, are each chosenfrom hydroxyl radicals and —NH₂ radicals, optionally substituted with atleast one radical chosen from C₁-C₄ alkyl radicals and linker arms Y;

[0161] linker arm Y is chosen from linear and branched divalent alkylenechains comprising from 1 to 14 carbon atoms, wherein said divalentalkylene chains may optionally be interrupted by at least onenitrogen-containing radical and optionally interrupted by at least oneheteroatom such as an oxygen atom, a sulphur atom or a nitrogen atom,further wherein said divalent alkylene chains may optionally beterminated with at least one nitrogen-containing radical and optionallyinterrupted by at least one heteroatom such as an oxygen atom, a sulphuratom or a nitrogen atom, and further wherein said divalent alkylenechains may optionally be substituted with at least one radical chosenfrom hydroxyl radicals and C₁-C₆ alkoxy radicals;

[0162] R₉ and R₁₀, which may be identical or different, are each chosenfrom a hydrogen atom, halogen atoms, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals, C₁-C₄aminoalkyl radicals and linker arms Y;

[0163] R₁₁, R₁₂, R₁₃, R₁₄, R₁₅ and R₁₆, which may be identical ordifferent, are each chosen from a hydrogen atom, linker arms Y and C₁-C₄alkyl radicals;

[0164] with the proviso that only one linker arm Y is present in eachcompound of formula (III).

[0165] Non-limiting examples of nitrogen-containing radicals of formula(III) include amino radicals, mono(C₁-C₄)alkylamino radicals,di(C₁-C₄)alkylamino radicals, tri(C₁-C₄)alkylamino radicals,monohydroxy(C₁-C₄)alkylamino radicals, imidazolinium radicals andammonium radicals.

[0166] Non-limiting examples of double bases of formula (III) includeN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylaminophenyl)tetramethylenediamine,N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methyl-phenyl)ethylenediamine,1,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane, and the acid addition saltsof any of the foregoing.

[0167] In one embodiment, double bases of formula (III) are chosen fromN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,1,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane and the acid addition saltsof any of the foregoing.

[0168] Non-limiting examples of para-aminophenols which may be usedaccording to the present invention include compounds of formula (IV) andthe acid addition salts thereof:

[0169] wherein:

[0170] R₁₇ is chosen from a hydrogen atom, halogen atoms, C₁-C₄ alkylradicals, C₁-C₄ monohydroxyalkyl radicals, (C₁-C₄)alkoxy(C₁-C₄)alkylradicals, C₁-C₄ aminoalkyl radicals andhydroxy(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; and

[0171] R₁₈ is chosen from a hydrogen atom, halogen atoms, C₁-C₄ alkylradicals, C₁-C₄ monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkylradicals, C₁-C₄ aminoalkyl radicals, cyano(C₁-C₄)alkyl radicals and(C₁-C₄)alkoxy(C₁-C₄)alkyl radicals,

[0172] with the proviso that at least one of R₁₇ and R₁₈ is a hydrogenatom.

[0173] Non-limiting examples of para-aminophenols of formula (IV)include of para-aminophenol, 4-amino-3-methylphenol,4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol,4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol,4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol,4-amino-2-(β-hydroxyethylaminomethyl)phenol, 4-amino-2-fluorophenol andthe acid addition salts of any of the foregoing.

[0174] Non-limiting examples of ortho-aminophenols which may be used asthe at least one oxidation base include 2-aminophenol,2-amino-5-methylphenol, 2-amino-6-methylphenol,5-acetamido-2-aminophenol and the acid addition salts of any of theforegoing.

[0175] Non-limiting examples of heterocyclic bases which may be used asthe at least one oxidation base include pyridine derivatives, pyrimidinederivatives, pyrazole derivatives and the acid addition salts of any ofthe foregoing.

[0176] Non-limiting examples of pyridine derivatives include compoundsdisclosed, for example, in British Patents GB 1 026 978 and GB 1 153196, the disclosures of which are incorporated herein by reference, suchas 2,5-diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine,2,3-diamino-6-methoxypyridine,2-(β-methoxyethyl)amino-3-amino-6-methoxypyridine, 3,4-diaminopyridineand the acid addition salts of any of the foregoing.

[0177] Non-limiting examples of pyrimidine derivatives include compoundsdescribed, for example, in German Patent DE 2 359 399, Japanese PatentsJP 88-169 571 and JP 91-10659, and Patent Application WO 96/15765, thedisclosures of which are incorporated herein by reference, such as2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine,2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidine,2,5,6-triaminopyrimidine, and pyrazolopyrimidine derivatives such asthose mentioned in French Patent Application FR-A-2 750 048, thedisclosure of which is incorporated herein by reference, such aspyrazolo[1,5-a]pyrimidine-3,7-diamine,2,5-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,pyrazolo[1,5-a]pyrimidine-3,5-diamine,2,7-dimethylpyrazolo[1,5-a]pyrimidine-3,5-diamine,3-aminopyrazolo[1,5-a]pyrimidin-7-ol,3—aminopyrazolo[1,5-a]pyrimidin-5-ol,2-(3-aminopyrazolo[1,5-a]pyrimidin-7-ylamino)ethanol,2-(7-aminopyrazolo[1,5-a]pyrimidin-3-ylamino)ethanol,2-[(3-aminopyrazolo[1,5-a]pyrimidin-7-yl)(2-hydroxyethyl)amino]ethanol,2-[(7-aminopyrazolo[1,5-a]pyrimidin-3-yl)(2-hydroxyethyl)amino]ethanol,5,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,5,N7,N7-tetramethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,3-amino-5-methyl-7-imidazolylpropylaminopyrazolo[1,5-a]pyrimidine, andthe addition salts and tautomeric forms (when there exists a tautomericequilibrium) of any of the foregoing.

[0178] Further non-limiting examples of pyrazole derivatives includecompounds described in German Patents DE 3 843 892 and DE 4 133 957 andPatent Applications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE 19543 988, the disclosures of which are incorporated hereby by reference,such as 4,5-diamino-1-methylpyrazole, 3,4-diaminopyrazole,4,5-diamino-1-(4′-chlorobenzyl)pyrazole,4,5-diamino-1-(β-hydroxyethyl)-pyrazole,4,5-diamino-1,3-dimethylpyrazole,4,5-diamino-1-(β-hydroxyethyl)pyrazole,4,5-diamino-3-methyl-1-phenylpyrazole,4,5-diamino-1-methyl-3-phenylpyrazole,4-amino-1,3-dimethyl-5-hydrazinopyrazole,1-benzyl-4,5-diamino-3-methylpyrazole,4,5-diamino-3-tert-butyl-1-methylpyrazole,4,5-diamino-1-tert-butyl-3-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)-3-methyl pyrazole,4,5-diamino-1-ethyl-3-methyl pyrazole,4,5-diamino-1-ethyl-3-(4′-methoxyphenyl)pyrazole,4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,4,5-diamino-3-hydroxymethyl-1-methylpyrazole,4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,4,5-diamino-3-methyl-1-isopropylpyrazole,4-amino-5-(2′-aminoethyl)amino-1,3-dimethylpyrazole,3,4,5-triaminopyrazole, 1-methyl-3,4,5-triaminopyrazole,3,5-diamino-1-methyl-4-methylaminopyrazole,3,5-diamino-4-(β-hydroxyethyl)amino-1-methylpyrazole and the acidaddition salts of any of the foregoing.

[0179] According to the present invention, the at least one oxidationbase may be present in the composition in an amount generally rangingfrom 0.0005% to 12% by weight relative to the total weight of the dyecomposition, such as from 0.005% to 6% by weight.

[0180] The dye composition according to the present invention mayoptionally further comprise at least one additional coupler differentfrom the indolizine derivatives of formula (I) and may optionallyfurther comprise at least one direct dye, for example, to vary and/orenrich the shade obtained using the at least one oxidation base withhighlights.

[0181] The at least one additional coupler which can be used in the dyecomposition according to the present invention may be chosen fromcouplers conventionally used in oxidation dyeing, such as, for example,meta-phenylenediamines, meta-aminophenols, meta-diphenols andheterocyclic couplers such as, for example, indole derivatives, indolinederivatives, benzimidazole derivatives, benzomorpholine derivatives,sesamol derivatives, pyridine derivatives, pyrimidine derivatives,pyrazole derivatives and the acid addition salts thereof.

[0182] In one embodiment, the at least one additional coupler is chosenfrom 2-methyl-5-aminophenol, 5-N-(β-hydroxyethyl)amino-2-methylphenol,3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene,4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, sesamol,1-amino-2-methoxy-4,5-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 6-hydroxyindoline,2,6-dihydroxy-4-methylpyridine, 1-H-3-methylpyrazol-5-one,1-phenyl-3-methylpyrazol-5-one and the addition salts of any of theforegoing.

[0183] When present, the at least one additional coupler may be presentin the composition in an amount generally ranging from 0.0001% to 10% byweight relative to the total weight of the dye composition, such as from0.005% to 5% by weight.

[0184] According to the present invention, the acid addition salts maybe chosen from hydrochlorides, hydrobromides, sulphates, tartrates,lactates and acetates.

[0185] The medium suitable for oxidation dyeing, or support, accordingto the present invention may be chosen from water and a mixture of waterand at least one organic solvent in order to dissolve the compoundswhich might not be sufficiently soluble in water alone. Non-limitingexamples of the at least one organic solvent include C₁-C₄ alkanols suchas ethanol and isopropanol; glycerol; glycols and glycol ethers such as2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether,diethylene glycol, diethylene glycol monomethyl ether; aromatic alcoholssuch as benzyl alcohol and phenoxyethanol; and analogous solvents.

[0186] According to the present invention, the at least one organicsolvent maybe present in the composition in an amount generally rangingfrom 1% to 40% by weight relative to the total weight of the dyecomposition, such as from 5% to 30% by weight.

[0187] The pH of the dye composition in accordance with the presentinvention generally ranges from 3 to 12. It can be adjusted to thedesired value by means of at least one agent commonly used in dyeingkeratin fibers chosen from acidifying agents and basifying agents.

[0188] Non-limiting examples of acidifying agents include inorganicacids and organic acids such as hydrochloric acid, orthophosphoric acid,carboxylic acids (such as tartaric acid, citric acid and lactic acid)and sulphonic acids.

[0189] Non-limiting examples of basifying agents include aqueousammonia, alkaline carbonates, alkanolamines such as mono-, di- andtriethanolamines and derivatives thereof, sodium hydroxide, potassiumhydroxide and compounds of formula (V):

[0190] wherein:

[0191] R₂₃ is chosen from divalent propylene residues, optionallysubstituted with at least one radical chosen from hydroxyl radicals andC₁-C₄ alkyl radicals;

[0192] R₁₉, R₂₀, R₂₁ and R₂₂, which may be identical or different, areeach chosen from a hydrogen atom, C₁-C₄ alkyl radicals and C₁-C₄hydroxyalkyl radicals.

[0193] According to the present invention, the dye composition mayfurther comprise at least one adjuvant chosen from adjuvantsconventionally used in hair dyeing compositions, such as anionicsurfactants, cationic surfactants, nonionic surfactants, amphotericsurfactants, zwitterionic surfactants, anionic polymers, cationicpolymers, nonionic polymers, amphoteric polymers, zwitterionic polymers,inorganic thickeners, organic thickeners, antioxidants, penetrationagents, sequestering agents, fragrances, buffers, dispersing agents,conditioners, such as, for example, silicones, film-forming agents,preserving agents and opacifiers.

[0194] Needless to say, a person skilled in the art will take care tochoose any optional additional compound(s) such that the advantageousproperties associated with the inventive dye compositions are not, ornot substantially, adversely affected by the addition(s) envisaged.

[0195] According to the present invention, the dye composition may beprovided in various forms, such as in the form of a liquid, a cream or agel, or in any other form suitable for dyeing keratin fibers, such ashuman hair.

[0196] Another subject of the present invention is a process foroxidation dyeing of keratin fibers comprising applying to said keratinfibers for a sufficient time to obtain a desired color at least one dyecomposition comprising, in a medium suitable for dyeing, (i) at leastone coupler chosen from indolizine derivatives of formula (I) and (ii)at least one oxidation base. In one embodiment, the keratin fibers arechosen from human keratin fibers. In another embodiment, the humankeratin fibers are hair.

[0197] In another embodiment, the at least one dye composition isapplied to the keratin fibers, and the desired color may be developed ata pH chosen from acidic, neutral or alkaline pH. Further, the at leastone dye composition may further comprise at least one oxidizing agentwhich may be added to the at least one dye composition at the time ofapplication, and/or which may be present in at least one oxidizingcomposition. In one embodiment, the at least one oxidizing compositionmay be applied simultaneously with said at least one dye composition,while in another embodiment, the at least one oxidizing composition maybe applied to the keratin fibers sequentially with the at least one dyecomposition.

[0198] In a further embodiment, the at least one dye composition ismixed, at the time of use, with at least one oxidizing compositioncomprising, in a medium appropriate for dyeing, at least one oxidizingagent present in an amount sufficient to develop a desired coloration.The mixture obtained may subsequently be applied to the keratin fibersand may be left to stand for 3 to 50 minutes, such as for 5 to 30minutes. In yet another embodiment, the fibers are rinsed, and mayoptionally be washed with a shampoo, rinsed again and dried.

[0199] According to the present invention, the at least one oxidizingagent may be chosen from oxidizing agents conventionally used for theoxidation dyeing of keratin fibers, such as hydrogen peroxide, ureaperoxide, alkali metal bromates, persalts such as perborates andpersulphates, peracids and enzymes such as peroxidases, laccases,tyrosinases and oxidoreductases (such as pyranose oxidases, glucoseoxidases, glycerol oxidases, lactate oxidases, pyruvate oxidases anduricases).

[0200] The pH of the at least one oxidizing composition comprising theat least one oxidizing agent after mixing with the at least one dyecomposition may generally range from 3 to 12, such as from 5 to 11.Further, the pH may be adjusted to a desired value by means of at leastone agent chosen from acidifying and basifying agents commonly in dyeingkeratin fibers and as defined above.

[0201] The at least one oxidizing composition as defined above may alsocontain at least one adjuvant conventionally used in hair dyeingcompositions and as defined above.

[0202] The composition which is applied to the keratin fibers may be invarious forms, such as in the form of a liquid, a cream or a gel or anyother form suitable for carrying out dyeing of keratin fibers, such ashuman hair.

[0203] The present invention also provides a multi-compartment device orkit or any other packaging system, comprising a first compartmentcontaining a first composition comprising at least one dye compositionas defined above and a second compartment containing a secondcomposition comprising at least one oxidizing composition as defined Aftabove. These devices may be equipped with a means allowing the desiredmixture to be deposited on the hair, such as the devices described inFrench Patent FR-2 586 913, the disclosure of which is incorporatedherein.

[0204] Finally, this invention provides certain novel indolizinederivatives of formula (I) These novel indolizine derivatives are chosenfrom methyl 2-methylindolizine-6carboxylate,7-methyl-2-(2,5-dimethoxyphenyl)indolizine and the acid addition saltsthereof.

[0205] According to the present invention, the acid addition salts ofthese novel compounds may be chosen from those defined above for thecompounds of formula (I). These specific compounds may be preparedaccording to the synthetic processes mentioned above for the compoundsof formula (I).

[0206] Other than in the operating example, or where otherwiseindicated, all numbers expressing quantities of ingredients, reactionconditions, and so forth used in the specification and claims are to beunderstood as being modified in all instances by the term “about.”Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present invention. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldbe construed in light of the number of significant digits and ordinaryrounding approaches.

[0207] Notwithstanding that the numerical ranges and parameters settingforth the broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. The following examples are intended toillustrate the invention without limiting the scope as a result. Thepercentages are given on a weight basis.

DYEING EXAMPLES EXAMPLES 1 TO 5 OF DYEING IN NEUTRAL MEDIUM

[0208] The following dye compositions, in accordance with the invention,were prepared: EXAMPLE 1 2 3 4 5 Methyl 2-methylindolizine-6- 3 × 10⁻³ 3× 10⁻³ 3 × 10⁻³ 3 × 10⁻³ — carboxylate (coupler of formula (I)) mol molmol mol 2-Methylindolizine - - - - 3 × 10⁻³ (coupler of formula (I)) molpara-Phenylenediamine 3 × 10⁻³ - - - - (oxidation base) molpara-Tolylenediamine - 3 × 10⁻³ - - - (oxidation base) mol3,7-Diaminopyrazolopyrimidine - - 3 × 10⁻³ - 3 × 10⁻³ dihydrochloride(oxidation base) mol mol N-(□-Methoxyethyl)-para- - - - 3 × 10⁻³ -phenylenediamine dihydrochloride mol (oxidation base) Common dye supportNo. 1 (*) (*) (*) (*) (*) Demineralized water qs 100 g 100 g 100 g 100 g100 g

[0209] At the time of use, each of the above dye compositions was mixedweight for weight with a 20-volumes hydrogen peroxide solution (6% byweight) of pH 3.

[0210] Each mixture obtained had a pH of approximately 6.8, and wasapplied for 30 minutes to locks of natural grey hair containing 90%white hairs. The locks were then rinsed, washed with shampoo, rinsedagain and then dried.

[0211] The shades obtained are given in the table below: Example Shadeobtained 1 very dark grey 2 dark green 3 violet 4 dark green-blue 5ash-violet dark blond

EXAMPLE 6 OF DYEING IN ALKALINE MEDIUM

[0212] The dye composition below, in accordance with the invention, wasprepared: EXAMPLE 6 2-Methylindolizine (coupler of formula (I)) 3 × 10⁻³mol 3,7-Diaminopyrazolopyrimidine dihydrochloride 3 × 10⁻³ mol(oxidation base) Common dye support No. 2 (**) Demineralized water qs100 g

[0213] At the time of use, the above dye composition was mixed weightfor weight with a 20-volume hydrogen peroxide solution (6% by weight) ofpH 3.

[0214] The mixture obtained had a pH of approximately 10, and wasapplied for 30 minutes to locks of natural grey hair containing 90%white hairs. The locks were then rinsed, washed with shampoo, rinsedagain and then dried.

[0215] The hair was dyed in an iridescent ash blond shade.

What is claimed is:
 1. A composition for oxidation dyeing of keratinfibers comprising, in a medium appropriate for dyeing keratin fibers:(i) at least one oxidation base; and (ii) at least one coupler chosenfrom indolizine derivatives of formula (I) and the acid addition saltsthereof:

wherein: n is an integer ranging from 0 to 4; R₁ and R₃, which may beidentical or different, are each chosen from a hydrogen atom; halogenatoms; C₁-C₄ alkyl radicals; C₁-C₄ alkoxy radicals; C₁-C₄monohydroxyalkyl radicals; C₂-C₄ polyhydroxyalkyl radicals; C₁-C₄aminoalkyl radicals; acetylamino radicals; acetylamino(C₁-C₄)alkylradicals; (C₁-C₄)alkoxy(C₁-C₄)alkyl radicals;mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals;di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; aminocarboxy(C₁-C₄)alkylradicals; acetyl(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; and aromaticrings, optionally substituted with at least one radical chosen fromhalogen atoms, C₁-C₄ alkyl radicals, trifluoromethyl radicals, C₁-C₄alkoxy radicals, amino radicals and mono- and disubstituted aminoradicals wherein the substituent is chosen from C₁-C₄ alkyl radicals,(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, di(C₁-C₄)alkylamino(C₁-C₄)alkylradicals, carboxyl radicals and sulphoxy radicals; wherein R₃ mayoptionally further be chosen from 5- and 6-membered unsaturatedheterocycles; and with the proviso that at least one of R₁ and R₃ is ahydrogen atom; R₂ and R₄, which may be identical or different, are eachchosen from a hydrogen atom, halogen atoms, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals, C₁-C₄aminoalkyl radicals, mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals, cyanoradicals, carboxy(C₁-C₄)alkyl radicals, nitro radicals, and 5- and6-membered aromatic rings, optionally substituted with at least oneradical chosen from halogen atoms, C₁-C₄ alkyl radicals, trifluoromethylradicals, C₁-C₄ alkoxy radicals, amino radicals and mono- anddisubstituted amino radicals wherein the substituent is chosen fromC₁-C₄ alkyl radicals, (C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals and sulphoxyradicals.
 2. A composition according to claim 1, wherein said keratinfibers are human keratin fibers.
 3. A composition according to claim 2,wherein said human keratin fibers are hair.
 4. A composition accordingto claim 1, wherein said aromatic rings of formula (I) are chosen fromphenyl rings, nitrophenyl rings, alkylphenyl rings, alkoxyphenyl rings,polyalkylphenyl rings and polyalkoxyphenyl rings.
 5. A compositionaccording to claim 1, wherein said unsaturated 5- or 6-memberedheterocycles are chosen from pyrrole rings, pyridine rings, pyrimidinerings, imidazole rings, pyrazole rings, oxazole rings, thiazole rings,triazole rings, pyrazolotriazole rings, pyrazoloimidazole rings,pyrrolotriazole rings, pyrazolopyrimidine rings, pyrazolopyridine rings,benzimidazole rings, benzoxazole rings, benzothiazole rings, indolerings, indoline rings, indolidine rings, isoindolidine rings,benzotriazoline rings, pyrazine rings, oxazine rings, triazine rings,quinoline rings, tetrahydroquinoline rings, benzimidazolidine rings andbenzopyrimidine rings.
 6. A composition according to claim 1 whereinsaid indolizine derivatives of formula (I) are chosen from: indolizine;2-methyl-1-phenylindolizine; 2,8-dimethylindolizine; methyl2-methylindolizine-6-carboxylate; 2,7-dimethylindolizine;2-methyl-1-(4-nitrophenyl)indolizine; 8-methyl-2-phenylindolizine;2-methylindolizine; 7-methyl-2-phenylindolizine; 2-phenylindolizine;7-methyl-2-(3-nitrophenyl)indolizine;7-methyl-2-(2,5-dimethoxyphenyl)indolizine; 2-(2-pyridyl)indolizine;2-(4-N,N-dimethylaminophenyl)indolizine;2-phenyl-3-[2-(4-pyridyl)ethyl]indolizine;2-phenyl-3-[2-(2-pyridyl)ethyl]indolizine; 2-ethyl-7-methoxyindolizine;2-ethyl-8-methoxyindolizine; ethyl 2-butyl-7-indolizinecarboxylate;1-ethylindolizine; 6,8-dimethylindolizine; 5-ethyl-7-methylindolizine;N,N-diethyl-2-methyl-1-indolizinethanamine;N,N-dimethyl-2-methyl-1-indolizinethanamine;N-ethyl-2-methyl-1-indolizinethanamine;N-methyl-2-methyl-1-indolizinethanamine; 2-methyl-1-indolizinethanamine;5,7-dimethylindolizine; 8-cyano-2-methylindolizine;1-ethyl-2-methylindolizine; 5-indolizineacetic acid; dihydroindolizine;1-indolizinealanine; 6-ethyl-1,2-dimethylindolizine; 3-ethylindolizine;2-ethyl-1-methylindolizine; N,N-diethyl-2-methyl-3-indolizinethanamine;N-ethyl-2-methyl-3-indolizinethanamine;N-ethyl-N-[2-(2-methyl-3-indolizinyl)ethyl]acetamide;N-[2-(2-methyl-3-indolizinyl)ethyl]acetamide;N,N,2-trimethyl-3-indolizinethanamine;N,2-dimethyl-3-indolizinethanamine; 2-methyl-3-indolizinethanamine;ethyl 7-indolizinecarboxylate; ethyl 6-indolizinecarboxylate;N,N-diethyl-2-methyl-3-indolizinepropanamine;N-ethyl-N-[3-(2-methyl-3-indolizinyl)propyl]acetamide;N-ethyl-2-methyl-3-indolizinepropanamine;N-[3-(2-methyl-3-indolizinyl)propyl]acetamide;N,N,2-trimethyl-3-indolizinepropanamine;N,2-dimethyl-3-indolizinepropanamine; 2-methyl-3-indolizinepropanamine;2-methyl-8-nitroindolizine; 2-methyl-6-nitroindolizine;N,N′-dimethyl-1,2-indolizinethanamine; methyl2-methyl-7-indolizinecarboxylate; ethyl2-methyl-7-indolizinecarboxylate; 2-methyl-7-indolizinecarboxamide;N-ethyl-2-indolizinethanamine; N-methyl-2-indolizinethanamine; ethyl2-methyl-8-indolizinecarboxylate; 2-methyl-8-indolizinecarboxylic acid;2-methyl-6-methoxyindolizine; 2,8-dimethylindolizine;8-methylindolizine; N-[(2-methyl-7-indolizinyl)methyl]acetamide;7-(aminomethyl)-2-methylindolizine; 2-methyl-7-indolizinecarboxamide;1-β-hydroxyethyl-2-methylindolizine; 6-hydroxymethyl-2-methylindolizine;ethyl 6-carboxy-2-methylindolizine; 1-hydroxymethylindolizine;2-aminomethylindolizine; 2-hydroxymethylindolizine;2,3,7trimethylindolizine; 2,3,6-trimethylindolizine; 5-methylindolizine;3,5-dimethylindolizine; 1-methylindolizine; 7-2-methylindolizine;7-methylindolizine; 6-methylindolizine; 3-methylindolizine;6-ethyl-2,3-dimethylindolizine; 6-ethyl-2-methylindolizine;1,2-dimethylindolizine; 2,7-dimethylindolizine; 2,6-dimethylindolizine;2,5-dimethylindolizine; 2,3-dimethylindolizine; 2-(3-furanyl)indolizine;2-(2-thiazolyl)indolizine; 2-(3-thienyl)indolizine;2-(2-thienyl)indolizine; 5,7-dimethyl-2-phenylindolizine;2-(3,4-dimethoxyphenyl)indolizine; 5-carboxy-2-phenylindolizine;4-(7-indolizinyl)benzenesulphonic acid;4-(2-indolizinyl)benzenesulphonic acid; 3,8-dimethyl-2-phenylindolizine;3,7-dimethyl-2-phenylindolizine; 3,6-dimethyl-2-phenylindolizine;3,5-dimethyl-2-phenylindolizine; 7-methyl-8-nitro-2-phenylindolizine;7-methyl-6-nitro-2-phenylindolizine; 1-β-aminoethyl-2-phenylindolizine;8-methyl-2-phenylindolizine; 2-(3-methoxyphenyl)indolizine;6-ethyl-2-phenylindolizine; 2-(2,5-dimethoxyphenyl)-5-methylindolizine;2-(2,5-dimethoxyphenyl)indolizine; 6-methyl-2-phenylindolizine;8-carboxy-2-phenylindolizine; 2-(4-γ-hydroxypropylphenyl)indolizine;2-(4-β-hydroxyethylphenyl)indolizine; 8-nitro-2-phenylindolizine;6-nitro-2-phenylindolizine; 6-carboxy-2-phenylindolizine;6-carboxy-2-phenylindolizine; 5-methyl-2-phenylindolizine;7-methoxy-2-phenylindolizine;1-[2-(dimethylamino)ethyl]-2-phenylindolizine;1-[3-(dimethylamino)propyl]-2-phenylindolizine;1-[(dimethylamino)methyl]-2-phenylindolizine;2-(4-methoxyphenyl)indolizine; and the acid addition salts of any of theforegoing.
 7. A composition according to claim 1, wherein said at leastone coupler is present in an amount ranging from 0.0005% to 12% byweight relative to the total weight of said composition.
 8. Acomposition according to claim 7, wherein said at least one coupler ispresent in an amount ranging from 0.005% to 6% by weight relative to thetotal weight of said composition.
 9. A composition according to claim 1,wherein said at least one oxidation base is chosen frompara-phenylenediamines, double bases, para-aminophenols,ortho-aminophenols and heterocyclic oxidation bases, and the acidaddition salts of the foregoing.
 10. A composition according to claim 9,wherein said para-phenylenediamines are chosen from compounds of formula(II) and the acid addition salts thereof:

wherein: R₅ is chosen from a hydrogen atom, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals,(C₁-C₄)alkoxy(C₁-C₄)alkyl radicals, C₁-C₄ alkyl radicals substitutedwith at least one radical chosen from nitrogen-containing radicals,phenyl radicals and 4′-aminophenyl radicals; R₆ is chosen from ahydrogen atom, C₁-C₄ alkyl radicals, C₁-C₄ monohydroxyalkyl radicals,C₂-C₄ polyhydroxyalkyl radicals, (C₁-C₄)alkoxy(C₁-C₄)alkyl radicals andC₁-C₄ alkyl radicals substituted with at least one nitrogen-containingradical; R₇ is chosen from a hydrogen atom, halogen atoms, C₁-C₄ alkylradicals, C₁-C₄ monohydroxyalkyl radicals, C₁-C₄ hydroxyalkoxy radicals,acetylamino(C₁-C₄)alkoxy radicals, mesylamino(C₁-C₄)alkoxy radicals andcarbamoylamino(C₁-C₄)alkoxy radicals; R₈ is chosen from a hydrogen atom,halogen atoms and C₁-C₄ alkyl radicals.
 11. A composition according toclaim 10, wherein said halogen atoms are chosen from chlorine atoms,bromine atoms, iodine atoms and a fluorine atoms.
 12. A compositionaccording to claim 10, wherein said nitrogen-containing radicals arechosen from amino radicals, mono(C₁-C₄)alkylamino radicals,di(C₁-C₄)alkylamino radicals, tri(C₁-C₄)alkylamino radicals,monohydroxy(C₁-C₄)alkylamino radicals, imidazolinium radicals andammonium radicals.
 13. A composition according to claim 10, wherein saidpara-phenylenediamines of formula (II) are chosen frompara-phenylenediamine, para-tolylenediamine,2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,4-amino-N,N-diethyl-3-methylaniline,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-N,N-bis(β-hydroxyethyl)amino-2-methylaniline,4-N,N-bis(β-hydroxyethyl)amino-2-chloroaniline,2-β-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine,2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,2-hydroxymethyl-para-phenylenediamine,N,N-dimethyl-3-methyl-para-phenylenediamine,N-ethyl-N-(β-hydroxyethyl)-para-phenylenediamine,N-(β,γ-dihydroxypropyl)-para-phenylenediamine,N-(4′-aminophenyl)-para-phenylenediamine,N-phenyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine, 2-β-acetylaminoethyloxy-para-phenylenediamine, N-(β-methoxyethyl)-para-phenylenediamine and theacid addition salts of any of the foregoing.
 14. A composition accordingto claim 13, wherein said para-phenylenediamines are chosen frompara-phenylenediamine, para-tolylenediamine,2-isopropyl-para-phenylenediamine,2,β-hydroxyethyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,3-dimethyl-para-phenylenediamine,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,2-chloro-para-phenylenediamine,2-β-acetylaminoethyloxy-para-phenylenediamine, and the acid additionsalts of any of the foregoing.
 15. A composition according to claim 9,wherein said double bases are chosen from compounds of formula (III) andthe acid addition salts thereof:

wherein: Z₁ and Z₂, which may be identical or different, are each chosenfrom hydroxyl radicals and —NH₂ radicals, optionally substituted with atleast one radical chosen from C₁-C₄ alkyl radicals and linker arms Y;linker arm Y is chosen from linear and branched divalent alkylene chainscomprising from 1 to 14 carbon atoms, wherein said divalent alkylenechains may optionally be interrupted by at least one nitrogen-containingradical and optionally interrupted by at least one heteroatom chosenfrom an oxygen atom, a sulphur atom and a nitrogen atom, further whereinsaid divalent alkylene chains may optionally be terminated with at leastone nitrogen-containing radical and optionally interrupted by at leastone heteroatom chosen from an oxygen atom, a sulphur atom and a nitrogenatom, and further wherein said divalent alkylene chains may optionallybe substituted with at least one radical chosen from hydroxyl radicalsand C₁-C₆ alkoxy radicals; R₉ and R₁₀, which may be identical ordifferent, are each chosen from a hydrogen atom, halogen atoms, C₁-C₄alkyl radicals, C₁-C₄ monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkylradicals, C₁-C₄ aminoalkyl radicals and linker arms Y; R₁₁, R₁₂, R₁₃,R₁₄, R₁₅ and R₁₆, which may be identical or different, are each chosenfrom a hydrogen atom, linker arms Y and C₁-C₄ alkyl radicals; with theproviso that only one linker arm Y is present in each compound offormula (III).
 16. A composition according to claim 15, wherein saiddouble bases of formula (III) are chosen fromN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylaminophenyl)tetramethylenediamine,N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine,1,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane and the acid addition saltsof any of the foregoing.
 17. A composition according to claim 16,wherein said double bases are chosen fromN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,1,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane and the acid addition saltsof any of the foregoing.
 18. A composition according to claim 9, whereinsaid para-aminophenols are chosen from compounds of formula (IV) and theacid addition salts thereof:

wherein: R₁₇ is chosen from a hydrogen atom, halogen atoms, C₁-C₄ alkylradicals, C₁-C₄ monohydroxyalkyl radicals, (C₁-C₄)alkoxy(C₁-C₄)alkylradicals, C₁-C₄ aminoalkyl radicals andhydroxy(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; and R₁₈ is chosen from ahydrogen atom, halogen atoms, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals, C₁-C₄aminoalkyl radicals, cyano(C₁-C₄)alkyl radicals and(C₁-C₄)alkoxy(C₁-C₄)alkyl radicals, with the proviso that at least oneof R₁₇ and R₁₈ is a hydrogen atom.
 19. A composition according to claim18, wherein said para-aminophenols of formula (IV) are chosen frompara-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol,4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol,4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol,4-amino-2-aminomethylphenol,4-amino-2-(β-hydroxyethylaminomethyl)phenol, 4-amino-2-fluorophenol andthe acid addition salts of any of the foregoing.
 20. A compositionaccording to claim 9, wherein said ortho-aminophenols are chosen from2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol,5-acetamido-2-aminophenol and the acid addition salts of any of theforegoing.
 21. A composition according to claim 9, wherein saidheterocyclic bases are chosen from pyridine derivatives, pyrimidinederivatives, pyrazole derivatives and the acid addition salts of any ofthe foregoing.
 22. A composition according to claim 1, wherein said atleast one oxidation base is present in an amount ranging from 0.0005% to12% by weight relative to the total weight of said composition.
 23. Acomposition according to claim 19, wherein said at least one oxidationbase is present in an amount ranging from 0.005% to 6% by weightrelative to the total weight of said composition.
 24. A compositionaccording to claim 1, further comprising at least one additional couplerdifferent from said indolizine derivatives of formula (I) and the acidaddition salts thereof.
 25. A composition according to claim 24, whereinsaid at least one additional coupler is chosen frommeta-phenylenediamines, meta-aminophenols, meta-diphenols, heterocycliccouplers and the acid addition salts thereof.
 26. A compositionaccording to claim 25, wherein said hetereocyclic couplers are chosenfrom indole derivatives, indoline derivatives, benzimidazolederivatives, benzomorpholine derivatives, sesamol derivatives, pyridinederivatives, e pyrimidine derivatives, pyrazole derivatives and the acidaddition salts thereof.
 27. A composition according to claim 24, whereinsaid at least one additional coupler is chosen from2-methyl-5-aminophenol, 5-N-(β-hydroxyethyl)amino-2-methylphenol,3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene,4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, sesamol,1-amino-2-methoxy-4,5-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 6-hydroxyindoline,2,6-dihydroxy-4-methylpyridine, 1-H-3-methylpyrazol-5-one,1-phenyl-3-methylpyrazol-5-one and the addition salts of any of theforegoing.
 28. A composition according to claim 24, wherein said atleast one additional coupler is present in an amount ranging from0.0001% to 10% by weight relative to the total weight of saidcomposition.
 29. A composition according to claim 28, wherein said atleast one additional coupler is present in an amount ranging from 0.005%to 5% by weight relative to the total weight of said composition.
 30. Acomposition according to claim 1, further comprising at least one directdye.
 31. A composition according to claim 1, wherein said acid additionsalts are chosen from hydrochlorides, hydrobromides, sulphates,tartrates, lactates and acetates.
 32. A composition according to claim1, wherein said medium suitable for dyeing is chosen from water and amixture of water and at least one organic solvent.
 33. A compositionaccording to claim 32, wherein said at least one organic solvent ischosen from C₁-C₄ alkanols, glycerol, glycols, glycol ethers andaromatic alcohols.
 34. A composition according to claim 32, wherein saidat least one organic solvent is present in an amount ranging from 1% to40% by weight relative to the total weight of said composition.
 35. Acomposition according to claim 1, wherein said composition has a pHranging from 3 to
 12. 36. A composition according to claim 1, whereinsaid composition is in the form of a liquid, a cream or a gel.
 37. Aprocess for oxidation dyeing of keratin fibers comprising: applying tosaid keratin fibers for a sufficient time to develop a desired color atleast one dye composition comprising, in a medium suitable for dyeing,(i) at least one oxidation base and (ii) at least one coupler chosenfrom indolizine derivatives of formula (I) and the acid addition saltsthereof:

wherein: n is an integer ranging from 0 to 4; R₁ and R₃, which may beidentical or different, are each chosen from a hydrogen atom; halogenatoms; C₁-C₄ alkyl radicals; C₁-C₄ alkoxy radicals; C₁-C₄monohydroxyalkyl radicals; C₂-C₄ polyhydroxyalkyl radicals; C₁-C₄aminoalkyl radicals; acetylamino radicals; acetylamino(C₁-C₄)alkylradicals; (C₁-C₄)alkoxy(C₁-C₄)alkyl radicals;mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals;di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; aminocarboxy(C₁-C₄)alkylradicals; acetyl(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; and aromaticrings, optionally substituted with at least one radical chosen fromhalogen atoms, C₁-C₄ alkyl radicals, trifluoromethyl radicals, C₁-C₄alkoxy radicals, amino radicals and mono- and disubstituted aminoradicals wherein the substituent is chosen from C₁-C₄ alkyl radicals,(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, di(C₁-C₄)alkylamino(C₁-C₄)alkylradicals, carboxyl radicals and sulphoxy radicals; wherein R₃ mayoptionally further be chosen from 5- and 6-membered unsaturatedheterocycles; and with the proviso that at least one of R₁ and R₃ is ahydrogen atom; R₂ and R₄, which may be identical or different, are eachchosen from a hydrogen atom, halogen atoms, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals, C₁-C₄aminoalkyl radicals, mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals, cyanoradicals, carboxy(C₁-C₄)alkyl radicals, nitro radicals, and 5- and6-membered aromatic rings, optionally substituted with at least oneradical chosen from halogen atoms, C₁-C₄ alkyl radicals, trifluoromethylradicals, C₁-C₄ alkoxy radicals, amino radicals and mono- anddisubstituted amino radicals wherein the substituent is chosen fromC₁-C₄ alkyl radicals, (C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals and sulphoxyradicals.
 38. A process according to claim 37, further comprisingapplying to said keratin fibers at least one oxidizing composition. 39.A process according to claim 37, wherein said at least one dyecomposition further comprises at least one oxidizing agent.
 40. Aprocess according to claim 37, wherein said desired color is developedat acidic, neutral or alkaline pH.
 41. A process according to claim 39,wherein said at least one oxidizing agent is added to said at least onedye composition at the time of application.
 42. A process according toclaim 38, wherein said at least one oxidizing composition comprises atleast one oxidizing agent.
 43. A process according to claim 38, whereinsaid at least one oxidizing composition is applied to said keratinfibers simultaneously with said at least one dye composition.
 44. Aprocess according to claim 38, wherein said at least one oxidizingcomposition is applied to said keratin fibers sequentially with said atleast one composition.
 45. A process according to claim 38, wherein saidat least one oxidizing composition is mixed with said at least one dyecomposition prior to said applying.
 46. A process according to claim 37,wherein said keratin fibers are human keratin fibers.
 47. A processaccordingly to claim 46, wherein said human keratin fibers are hair. 48.A process according to claim 39, wherein said at least one oxidizingagent is chosen from hydrogen peroxide, urea peroxide, alkali metalbromates, persalts, peracids and enzymes.
 49. A process according toclaim 48, wherein said persalts are chosen from perborates andpersulphates.
 50. A process according to claim 48, wherein said enzymesare chosen from peroxidases, laccases, tyrosinases and oxidoreductases.51. A process according to claim 50, wherein said oxidoreductases arechosen from pyranose oxidase, glucose oxidase, glycerol oxidase, lactateoxidase, pyruvate oxidase and uricase.
 52. A process according to claim42, wherein said at least one oxidizing agent is chosen from hydrogenperoxide, urea peroxide, alkali metal bromates, persalts, peracids andenzymes.
 53. A process according to claim 52, wherein said persalts arechosen from perborates and persulphates.
 54. A process according toclaim 52, wherein said enzymes are chosen from peroxidases, laccases,tyrosinases and oxidoreductases.
 55. A process according to claim 54,wherein said oxidoreductases are chosen from pyranose oxidase, glucoseoxidase, glycerol oxidase, lactate oxidase, pyruvate oxidase anduricase.
 56. A process according to claim 37, wherein said sufficienttime to develop a desired color ranges from 3 minutes to 50 minutes. 57.A process according to claim 56, wherein said sufficient time to developa desired color ranges from 5 minutes to 30 minutes.
 58. A processaccording to claim 37, further comprising rinsing said keratin fibers.59. A process according to claim 58, further comprising washing saidkeratin fibers with shampoo.
 60. A process according to claim 59,further comprising rinsing and drying said keratin fibers.
 61. A processaccording to claim 45, wherein the pH of said at least one oxidizingcomposition mixed with said at least one dye composition ranges from 3to
 12. 62. A process according to claim 61, wherein the pH of said atleast one oxidizing composition mixed with said at least one dyecomposition ranges from 5 to
 11. 63. A multicompartment device or kitfor oxidation dyeing of keratin fibers comprising a first compartmentcontaining a first composition comprising, in a medium suitable fordyeing, (i) at least one oxidation base and (ii) at least one couplerchosen from indolizine derivatives of formula (I) and the acid additionsalts thereof:

wherein: n is an integer ranging from 0 to 4; R₁ and R₃, which may beidentical or different, are each chosen from a hydrogen atom; halogenatoms; C₁-C₄ alkyl radicals; C₁-C₄ alkoxy radicals; C₁-C₄monohydroxyalkyl radicals; C₂-C₄ polyhydroxyalkyl radicals; C₁-C₄aminoalkyl radicals; acetylamino radicals; acetylamino(C₁-C₄)alkylradicals; (C₁-C₄)alkoxy(C₁-C₄)alkyl radicals;mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals;di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; aminocarboxy(C₁-C₄)alkylradicals; acetyl(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals; and aromaticrings, optionally substituted with at least one radical chosen fromhalogen atoms, C₁-C₄ alkyl radicals, trifluoromethyl radicals, C₁-C₄alkoxy radicals, amino radicals and mono- and disubstituted aminoradicals wherein the substituent is chosen from C₁-C₄ alkyl radicals,(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, di(C₁-C₄)alkylamino(C₁-C₄)alkylradicals, carboxyl radicals and sulphoxy radicals; wherein R₃ mayoptionally further be chosen from 5- and 6-membered unsaturatedheterocycles; and with the proviso that at least one of R₁ and R₃ is ahydrogen atom; R₂ and R₄, which may be identical or different, are eachchosen from a hydrogen atom, halogen atoms, C₁-C₄ alkyl radicals, C₁-C₄monohydroxyalkyl radicals, C₂-C₄ polyhydroxyalkyl radicals, C₁-C₄aminoalkyl radicals, mono(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals, cyanoradicals, carboxy(C₁-C₄)alkyl radicals, nitro radicals, and 5- and6-membered aromatic rings, optionally substituted with at least oneradical chosen from halogen atoms, C₁-C₄ alkyl radicals, trifluoromethylradicals, C₁-C₄ alkoxy radicals, amino radicals and mono- anddisubstituted amino radicals wherein the substituent is chosen fromC₁-C₄ alkyl radicals, (C₁-C₄)alkylamino(C₁-C₄)alkyl radicals,di(C₁-C₄)alkylamino(C₁-C₄)alkyl radicals, carboxyl radicals and sulphoxyradicals; and a second compartment containing a second compositioncomprising at least one oxidizing composition.
 64. A compound chosenfrom methyl 2-methylindolizine-6-carboxylate,7-methyl-2-(2,5-dimethoxyphenyl)indolizine and the acid addition saltsthereof.